Numerical Study On Quenching Characteristics Of Premixed Flame In Crimped Ribbon Flame Arrester Structural Element

The flame arrester can well prevent the flame propagation and re-tempering explosion caused by the explosion of combustible gas.Among them,the crimped ribbon flame arrester is widely used in pipeline oil and gas storage and transportation,coal mines and other fields due to its excellent flame retardancy and flow performance.The flame extinguished when it passes through the flame-resistant structural element formed by the crimped ribbon construction is characterized as triangular slit quenching.Therefore,studying the quenching characteristics of the premixed flame in the triangular slit structure is helpful to the design of the crimped ribbon flame arrester and the suppression of combustible gas.In this paper,three premixed flames mixed in stoichiometric ratio of methane-air,ethylene-air,and propane-air propagating at different velocities are used as research objects.FLUENT is used to numerically simulate the propagation and quenching of a premixed flame in an equilateral triangular slit structure under different conditions,the flame propagation characteristics of the premixed flame in the triangular slit are obtained,and the influence of different factors on the flame propagation and extinction is pointed out.After that,the distance between the position of the flame propagation and the entrance(quenching length)is used as a measure of the difficulty of quenching,and the relationship curves between the quenching length of three different fuel-air premixed flames and the flame velocity,slit size,and initial wall temperature.The image intuitively reflects the negative effect of the triangular flame retardant unit on the flame quenching.The calculation formula of quenching length is obtained by fitting a large number of simulation data,and the flame quenching position can be better predicted by calculation to determine the thickness of the flame retardant layer.The results show that the different premixed flames propagate and quench in the triangular slit structure with similar characteristics that the flames shrink slightly after propagating forward to the limit distance and remain almost unchanged.At the same time,the high temperature of combustion generated by the heat dissipation of the wall transitions to the unburned area.The higher the adiabatic combustion temperature,the longer the flame propagation length,the greater the corresponding quenching length.For the same premixed flame,the quenching length have a positive correlation with flame velocity,the size of the slit,and the initial wall temperature.As the flame propagates faster,the increase in quenching length gradually slows down;When the flame propagates into the entrance with a higher velocity,the effect of the slit size on the flame quenching length is more obvious than the initial wall temperature.